Box lubrication pump

ABSTRACT

A box lubricator that includes a pump with a piston housing and piston. The piston housing extends from a first end to a second end, and includes a bore extending through the piston housing from the first end of the piston housing to the second end of the piston housing. The piston housing also includes a recess disposed at the second end of the piston housing, the recess being concentric with the bore and comprising a diameter larger than a diameter of the bore. The piston is disposed inside the bore of the piston housing. At least one elastomeric seal is disposed inside the recess of the piston housing and around the piston. In some embodiments, a ball and socket joint connects the piston to the rocker arm assembly. In some embodiments, a fluid passage and a check valve are disposed inside the piston.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of U.S. application Ser. No.14/343,954, titled “BOX LUBRICATION PUMP”, filed Mar. 10, 2014 which isa U.S. National Stage application of International Application No.PCT/US2012/066377 filed Nov. 21, 2012. U.S. National Stage applicationof International Application No. PCT/US2012/066377 filed Nov. 21, 2012claims priority to U.S. Provisional Patent Application Ser. No.61/562,811 entitled “SEALED LUBRICATION PUMP,” filed Nov. 22, 2011.

BACKGROUND

Box lubrication pumps are modular pumps that provide pump-to-pointlubrication, allowing consumers to adapt a lubrication system to analready existing system or machine without replacing or overhauling thesystem or machine. Box lubrication pumps are commonly used inmanufacturing, refining, and gas transmission applications to lubricatepiston assemblies and high speed bearings. They are also used in thelumber industry to lubricate and cool blades, guides, edgers, planers,and band saws. They have also been used in the rubber industry tolubricate dust stop seals on mixers. Box lubrication pumps arecost-effective and robust due to their simple, self-lubricating design.

In the prior art, box lubrication pumps are available in three differentconfigurations: pressure fed, gravity fed, and suction fed. Eachconfiguration includes as many as one to twenty four individual pumpsmounted to a reservoir box, each pump having a rocker arm assemblylocated inside of the reservoir box. A motor-driven camshaft assemblylocated inside of the reservoir box actuates the rocker arm assembly,which in turn actuates a piston inside of each pump. The camshaftassembly, the rocker arm assembly, and the interface between the rockerarm assembly and piston are submerged in and lubricated by fluid housedinside the reservoir box. As the piston inside each pump is actuated bythe rocker arm assembly, the piston pushes the fluid through a dischargeoutlet of each pump. In pressure fed configured pumps, fluid is pressurefed to the piston through an inlet line connected to a second reservoirseparate from the reservoir box to which each pump is mounted. Ingravity fed configured pumps, fluid is gravity fed to the piston throughan inlet line connected to a second reservoir located above the pumpsand separate from the reservoir box to which each pump is mounted. In asuction fed configured pump, the piston of each pump draws fluid fromthe reservoir box to which the pumps are mounted through a suction tubewhich extends from each pump into the reservoir box and into the fluidhoused inside the reservoir box. In summary, gravity fed configured or apressure fed configured pumps are attached to a reservoir box thatlubricates their respective rocker arm assemblies yet they pump fluidthat is located in a second and separate reservoir, while suction fedconfigured pumps pump fluid from the same reservoir that lubricatestheir rocker arm assemblies.

While the rocker arm assemblies of each pump configuration arelubricated by the fluid inside of the reservoir box, the pistons in eachpump configuration are lubricated by the fluid that the pistons pump. Inthe suction fed configured pumps, the pistons are lubricated by fluidhoused inside the reservoir box as they pump the same fluid out of thereservoir box. In pressure fed configured or gravity fed configuredpumps, the pistons are lubricated by the same fluid that they pump outof the second reservoir. In all three pump configurations, the fluidlubricating the pistons leaks off the pistons and drains into thereservoir box. Because the fluid lubricating the pistons leaks into thereservoir box, the fluid inside the reservoir box must be the same kindof fluid as the fluid pumped by the pistons. Thus, in the case of thepressure fed configured or gravity fed configured pumps, the secondreservoir must house the same kind of lubricating fluid as the reservoirbox to which the pumps are mounted.

Because prior art box lubrication pumps must house the same kind offluid inside their reservoir boxes that they pump, the fluid selectedand housed is the fluid with the properties that meets the lubricationneeds of the end activity to which the fluid is pumped by the boxlubrication pumps. In many cases, the lubricating needs required by theend activity are different from the lubrication needs of the boxlubrication pumps themselves, yet the box lubrication pumps must makedue self-lubricating themselves with the fluid needed by the endactivity, even when that fluid is less-than-ideal for the lubricationneeds of the box lubrication pumps. Because the box lubrication pumps inthese cases are self-lubricating with less-than-ideal fluid, theyexperience reduced performance, increased wear, and reduced life.

SUMMARY

According to the present invention, a box lubricator that includes apump with a piston housing and piston. The piston housing extends from afirst end to a second end, and includes a bore extending through thepiston housing from the first end of the piston housing to the secondend of the piston housing. The piston housing also includes a recessdisposed at the second end of the piston housing, the recess beingconcentric with the bore and comprising a diameter larger than adiameter of the bore. The piston is disposed inside the bore of thepiston housing. At least one elastomeric seal may be disposed inside therecess of the piston housing and around the piston.

In another embodiment of the present invention, a piston assemblyincludes a piston housing with a first end opposite a second end, a boreextending completely through the piston housing from the first end tothe second end of the piston housing, and a piston housing inletintersecting the bore between the first end and the second end of thepiston housing. The piston housing also includes an outlet disposed atthe second end of the piston housing and in fluid communication with thebore. A piston is disposed inside the bore of the piston housing and hasa first end opposite a second end. The piston also has a fluid passageformed inside the piston that fluidly connects the piston housing inletwith the piston housing outlet. A first recess is formed inside thefirst end of the piston and is in fluid communication with the fluidpassage. The first recess has a diameter smaller than a diameter of thepiston yet larger than a diameter of the fluid passage. A check ball anda retaining guide are disposed inside the first recess. The retainingguide limits displacement of the check ball to the first recess.

In another embodiment of the present invention, a pump includes asupport post with a first end opposite a second end, and a pistonhousing that also includes a first end to a second end. The pistonhousing also includes a bore extending through the piston housing fromthe first end to the second end of the piston housing. A piston isdisposed inside the bore of the piston housing and includes a first endopposite a second end. The pump also includes a rocker arm assemblyextending from the second end of the support post to the second end ofthe piston. The rocker arm assembly is pivotally connected to the secondend of the support post and is also connected to the second end of thepiston by a ball and socket joint.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a motor and a box lubrication pump withmultiple pumps.

FIG. 2 is a top view of the motor and box lubrication pump with multiplepumps of FIG. 1.

FIG. 3 is a side view of one of the pumps from the box lubrication pumpof FIG. 1.

FIG. 4 is a cross sectional view of the pump of FIG. 3.

FIG. 5 is an enlarged cross sectional view of a piston of the pump ofFIG. 4.

FIG. 6A is an enlarged cross sectional view of a first end of the pistonof FIG. 5 with a check valve in a closed position.

FIG. 6B is another enlarged cross sectional view of the first end of thepiston of FIG. 5 with a check valve in an open position.

FIG. 7 is an exploded perspective view of the first end of the piston ofFIG. 6.

FIG. 8 is an enlarged cross sectional view of a piston seal assembly ofthe pump of FIG. 4.

FIG. 9 is an enlarged cross sectional view of a ball and socket jointconnecting a rocker assembly to a second end of a piston of the pump ofFIG. 4.

FIG. 10 is a partial exploded view of the ball and socket joint of FIG.9.

FIG. 11 is an enlarged cross sectional view of another embodiment of aball and socket joint connecting a rocker assembly to a second end of apiston of a pump.

DETAILED DESCRIPTION

FIG. 1 is a front view of box lubricator 10 and FIG. 2 is a top view ofbox lubricator 10. Box lubricator 10 includes motor 12, torquetransmitter 14, gear reducer 16, camshaft 18, fluid reservoir 20,mounting base 22, pumps 24, bolts 26, lubrication lines 28, andlubrication points 30. In the embodiment of FIGS. 1 and 2, fluidreservoir 20 includes top plate 32, openings 34 (shown in FIGS. 3 and 4)formed in top plate 32, first sidewall 36, second sidewall 38, bottomsurface 40, first endwall 42, second endwall 44, cap 46, drain plug 48,and sight gauge 50.

Fluid reservoir 20 bottom surface 40 is joined to first sidewall 36,second sidewall 38, first endwall 42, second endwall 44 in an open boxgeometry such that first sidewall 36 is parallel to second sidewall 38and first endwall 42 is parallel to second endwall 44. Fluid reservoir20 top plate 32 is joined to first sidewall 36, second sidewall 38,first endwall 42, and second endwall 44 opposite bottom surface 40 toform fluid reservoir 20 in a closed box geometry. Top plate 40 of fluidreservoir 20 includes cap 46 which can be removed to fill fluidreservoir 20 with fluid and replaced once fluid reservoir 20 carries thedesired amount of fluid. Sight gauge 50 is disposed on first sidewall 36and permits visual inspection of the level of fluid inside fluidreservoir 20. Drain plug 48 may be connected to first sidewall 36,second sidewall 38, bottom surface 40, first endwall 42, or secondendwall 44 of fluid reservoir 20. In the embodiment of FIGS. 1 and 2,drain plug 48 is connected to second endwall 44. Fluid inside of fluidreservoir 20 can be drained from fluid reservoir 20 by removing drainplug 48 from second endwall 44.

Openings 34 (shown in FIGS. 3 and 4) are formed in top plate 32 of fluidreservoir 20 and sized to receive pumps 24 and permit pumps 24 to extendinto fluid reservoir 20. Pumps 24 are mounted to top plate 32 of fluidreservoir 20 by bolts 26. In the embodiment of FIGS. 1 and 2, sixopenings 34 are formed into top plate 32 and six pumps 24 are mounted totop plate 32 of fluid reservoir 20. Though the embodiments of FIGS. 1and 2 show six pumps 24, it will be appreciated by one skilled in theart that top plate 32 may include less than six openings 34 or more thansix openings 34, and that less than six pumps 24 or more than six pumps24 may be mounted to top plate 32 of fluid reservoir 20. Camshaft 18enters into fluid reservoir 20 through first endwall 42 and extendshorizontally into fluid reservoir 20 towards second endwall 44. Gearreducer 16 is connected to camshaft 18 outside of fluid reservoir 20.Torque transmitter 14 is connected to motor 12 and gear reducer 16 andtransmits torque from motor 12 to gear reducer 16. Gear reducer 16transmits torque to camshaft 18 and adjusts the rotational speed ofcamshaft 18. Motor 12 and fluid reservoir 20 are mounted inline ontomounting base 22. Torque transmitter 14 and gear reducer 16 may also bemounted onto mounting base 22 inline with motor 12 and fluid reservoir20.

As described below in the description of FIGS. 3, 4, 9 and 10, camshaft18 contacts pumps 24 inside fluid reservoir 20 and rotation of camshaft18 by motor 12 actuates pumps 24. Lubrication lines 28 fluidly connectpumps 24 to lubrication points 30 such that pumps 24, when actuated bymotor 12 and camshaft 18, may deliver fluid to lubrication points 30through lubrication lines 28. Each pump 24 is individually connected toone lubrication line 28, and each lubrication line 28 is connected toone or more lubrication points 30. Pumps 24 may pump fluid from insidereservoir 20 to lubrication points 30, or pumps 24 may pump fluid from adifferent reservoir than the fluid reservoir 20 to lubrication points30. The fluid in the different reservoir may be different in compositionfrom the fluid inside fluid reservoir 20.

FIG. 3 is an enlarged cross sectional view of box lubricator 10 takenalong line 3-3 and showing a side view of one of pumps 24. Boxlubricator 10 includes camshaft 18, fluid reservoir 20, pump 24, andbolts 26. In the embodiment of FIG. 3, camshaft 18 includes cam 52. Inthe embodiment of FIG. 3, fluid reservoir 20 includes top plate 32,opening 34 and fluid 54. In the embodiment of FIG. 3, pump 24 includesmain body 56, support post 58, piston housing 60, piston 62, rocker armassembly 64, pivot joint 66, ball and socket joint 68, pump inlet tube70, pump inlet strainer 72, adjustment screw 74, sight well 76, pumpoutlet assembly 78, and spring 80. In the embodiment of FIG. 3, mainbody 56 includes first surface 82 opposite second surface 84. In theembodiment of FIG. 3, support post 58 includes support post first end 86and support post second end 88. In the embodiment of FIG. 3, pistonhousing 60 includes piston housing first end 90 and piston housingsecond end 92.

Fluid reservoir 20 comprises a box geometry that is closed by top plate32. Fluid 54 is disposed inside fluid reservoir 20. Opening 34 is formedin top plate 32 of fluid reservoir 20 and sized to receive pump 24 andpermit pump 24 to extend into fluid reservoir 20. Pump 24 is mounted totop plate 32 of fluid reservoir 20 by bolts 26. Camshaft 18 extendshorizontally into fluid reservoir 20. Cam 52 is disposed on camshaft 18inside fluid reservoir 20 and adjacent pump 24. When pump 24 is mountedonto top plate 32, second surface 84 of main body 56 of pump 24 is nextto top plate 32 and covers opening 34 of top plate 32 of fluid reservoir20. Main body 56 of pump 24 extends outside of fluid reservoir 20 fromsecond surface 84 to first surface 82. Main body 56 may be a bracket.Bolts 26 extend through first surface 82 and second surface 84 of mainbody 56 and through top plate 32 of fluid reservoir 20 and anchor mainbody 56 of pump 24 to top plate 32 of fluid reservoir 20. In theembodiment of FIG. 3, there are two bolts 26 anchoring main body 56 ofpump 24 to top plate 32 of fluid reservoir 20. Support post 58 extendsfrom second surface 84 of main body 56, through opening 34 formed in topplate 32 of fluid reservoir 20, to support post second end 88 insidefluid reservoir 20. Support post 58 also extends outside of fluidreservoir 20, past first surface 82 of main body 56, to support postfirst end 86. Support post 58 may be integral with main body 56 orsupport post 58 may be manufactured separate from main body 56 andsubsequently connected to main body 56. Support post 58 may becylindrical.

Piston housing 60 is in close proximity to support post 58 and extendsfrom second surface 84 of main body 56, through opening 34 formed in topplate 32 of fluid reservoir 20, to piston housing second end 92 insidefluid reservoir 20. Piston housing second end 92 is disposed insidefluid reservoir 20 directly above camshaft 18 and cam 52. Piston housing60 also extends outside of fluid reservoir 20, past first surface 82 ofmain body 56, to piston housing first end 90. Piston housing 60 may beintegral with main body 56 or piston housing 60 may be manufacturedseparate from main body 56 and subsequently connected to main body 56.Piston housing 60 may be cylindrical. Adjustment screw 74 extendsthrough first surface 82 and second surface 84 of main body 56, throughopening 34 of top plate 32 of fluid reservoir 20, and into fluidreservoir 20. Adjustment screw 74 is in close proximity to support post58 opposite piston housing 60.

Piston 62 is disposed inside piston housing 60 and partially extendsfrom piston housing second end 92 into fluid reservoir 20. Pivot joint66 connects rocker arm assembly 64 to support post second end 88. Rockerarm assembly 64 extends from pivot joint 66 and support post second end88 towards piston housing 60 and extends between piston housing secondend 92 and cam 52 of camshaft 18. Rocker arm assembly 64 also extendsfrom pivot joint 66 and support post second end 88 towards adjustmentscrew 74. The distance between second surface 84 of main body 56 andpiston housing second end 92 is generally shorter than the distancebetween second surface 84 of main body 56 and support post second end88, thereby allowing rocker arm assembly 64 the ability to rotate onpivot joint 66 and support post second end 88. Support post second end88 also extends into fluid reservoir 20 further than adjustment screw 74so that rocker arm assembly 64 is capable of rotating on pivot joint 66and support post second end 88. Ball and socket joint 68 connects piston62 to rocker arm assembly 64 between piston housing second end 92 andcam 52. Spring 80 is disposed around piston housing 60 and extendsbetween second surface 84 of main body 56 and rocker arm assembly 64.When cam shaft 18 is rotated, cam 52 and spring 80 move piston 62between a down stroke position and an up stroke position. Adjustmentscrew 74 regulates the distance in which spring 80 may push piston 62down towards cam 52 by limiting the distance rocker arm assembly 64 mayrotate on support post second end 88.

Pump inlet tube 70 is connected to support post second end 88 andextends away from support post second end 88 further into fluidreservoir 20. Pump inlet strainer 72 is connected to pump inlet tube 70opposite support post second end 88 and strains fluid 54 that enterspump 24. Fluid 54 is disposed inside fluid reservoir 20 and typicallymaintained at a level sufficient to submerge pump inlet strainer 72,most of pump inlet tube 70, camshaft 18, cam 52, and rocker arm assembly64. As described below in FIG. 4, pump inlet tube 70 fluidlycommunicates with piston housing 60 and piston 62 through support post58 thereby providing fluid 54 a path to travel from fluid reservoir 20to piston housing 60. Sight well 76 is connected to support post firstend 86 and permits visual inspection of fluid 54 traveling throughsupport post 58 to piston housing 60. Pump outlet assembly 78 isconnected to piston housing first end 90. In the embodiment of FIG. 3,piston 62 pumps fluid 54 from fluid reservoir 20, through pump inletstrainer 72, pump inlet tube 70, support post 58, and piston housing 60,and into pump outlet assembly 78. Pump outlet assembly directs fluid 54away from pump 24.

FIG. 4 is a cross-sectional view of fluid reservoir 20 and pump 24 takenalong line 4-4 in FIG. 2. Box lubricator 10 includes camshaft 18, fluidreservoir 20, pump 24, and bolts 26. In the embodiment of FIG. 4,camshaft 18 includes cam 52. In the embodiment of FIG. 4, fluidreservoir 20 includes top plate 32, opening 34 and fluid 54. In theembodiment of FIG. 4, pump 24 includes main body 56, support post 58,piston housing 60, piston 62, rocker arm assembly 64, pivot joint 66,ball and socket joint 68, pump inlet tube 70, pump inlet strainer 72,adjustment screw 74, sight well 76, pump outlet assembly 78, spring 80,drip tube 94, and seal assembly 96. In the embodiment of FIG. 4, mainbody 56 includes first surface 82 and second surface 84. In theembodiment of FIG. 4, support post 58 includes support post first end86, support post second end 88, pump inlet passage 98, and fluid pathway100. In the embodiment of FIG. 4, piston housing 60 includes pistonhousing first end 90, piston housing second end 92, bore 102, pistonhousing inlet 104, and piston housing outlet 106. In the embodiment ofFIG. 4, piston 62 includes piston first end 108, piston second end 110,fluid passage 112, and first check valve 114. In the embodiment of FIG.4, sight well 76 includes window 116. In the embodiment of FIG. 4, pumpoutlet assembly 78 includes pump outlet passage 118, second check valve120, and third check valve 122.

In FIG. 4, components of like numbering with the components of FIG. 3are assembled as discussed above with reference to FIG. 3. Pump inletpassage 98 is formed inside support post 58 and extends through supportpost 58 from support post second end 88 to support post first end 86.Pump inlet tube 70 is connected to support post second end 88 andextends away from support post second end 88 further into fluidreservoir 20. Pump inlet strainer 72 is connected to pump inlet tube 70opposite support post second end 88 and strains fluid 54 that enterspump 24. Fluid pathway 100 is also formed inside support post 58 andextends from support post first end 86 towards support post second end88, exiting support post 58 between first surface 82 and second surface84 of main body 56 of pump 24. Drip tube 94 is connected inside pumpinlet passage 98 at support post first end 86 and extends away fromsupport post first end 86 while curving back in a candy-cane fashiontowards support post first end 86 and fluid pathway 100 withoutcontacting fluid pathway 100. Sight well 76 is connected to support postfirst end 86 and covers support post first end 86 and drip tube 94.Sight well 76 includes window 116 which is transparent and permitsvisual inspection of fluid 54 traveling through support post 58 and driptube 94 to piston housing 60. When fluid 54 enters pump 24, fluid 54travels into pump inlet tube 70 through pump inlet strainer 72. Fluid 54passes from pump inlet tube 70 into support post 58 through pump inletpassage 98. Fluid 54 then travels through pump inlet passage 98 and upinto drip tube 94 where it will exit drip tube 94 and fall back intosupport post 58 through fluid pathway 100. Fluid pathway 100 directsfluid 54 towards piston housing 60.

Bore 102 is formed in piston housing 60 and extends from piston housingsecond end 92 through piston housing first end 90. Piston housing inlet104 is formed in piston housing 60 between piston housing first end 90and piston housing second end 92, and intersects bore 102. When pistonhousing 60 is attached to main body 56 of pump 24, piston housing inlet104 is disposed on piston housing 60 between first surface 82 and secondsurface 84 of main body 56 adjacent to fluid pathway 100 of support post58 and fluidly communicates with fluid pathway 100 through a passagewithin main body 56. In the embodiment of FIG. 4, fluid pathway 100 mayextend into main body 56 between support post 58 and piston housing 60to connect with piston housing inlet 104. Piston housing outlet 106 isdisposed on piston housing first end 90 and may be integral with bore102 at piston housing first end 90. Pump outlet assembly 78 is connectedto piston housing first end 90. Pump outlet passage 118 extends throughpump outlet assembly 78 and is next to and concentric with pistonhousing outlet 106. Second check valve 120 and third check valve 122 aredisposed inside pump outlet passage 118 of pump outlet assembly 78.

Piston 62 is disposed inside bore 102 of piston housing 60 and extendsin a generally cylindrical geometry from piston first end 108 to pistonsecond end 110. Piston first end 108 is disposed inside bore 102proximate piston housing first end 90 and piston second end 110 extendsout of bore 102 through piston housing second end 92 into fluidreservoir 20. Fluid passage 112 is formed in piston 62 and extends frompiston first end 108 towards piston second end 110, exiting piston 62into bore 102 between first surface 82 and second surface 84 of mainbody 56 of pump 24. First check valve 114, which is discussed in greaterdetail below with reference to FIGS. 6 and 7, is formed inside pistonfirst end 108 and is aligned with and fluidly communicates with fluidpassage 112 inside piston 62. Seal assembly 96 is disposed inside pistonhousing 60 and around piston 62 between piston housing inlet 104 andpiston housing second end 92. Seal assembly 96, which is discussed ingreater detail below with reference to FIG. 8, fluidly seals pistonhousing 60 and piston 62 such that fluid 54 travels through pump 24without leaking back into fluid reservoir 20 through piston 62 andpiston housing 60.

When piston 62 in the embodiment of FIG. 4 actuates between an up anddown stroke, fluid 54 in fluid reservoir 20 enters pump 24 through pumpinlet strainer 72 and pump inlet tube 70. Fluid 54 passes from pumpinlet tube 70 into support post 58 through pump inlet passage 98. Fluid54 then travels through pump inlet passage 98 and up into drip tube 94where it will exit drip tube 94 and fall back into support post 58through fluid pathway 100. Fluid pathway 100 directs fluid 54 intopiston housing 60 through piston housing inlet 104, and piston housinginlet 104 directs fluid 54 into bore 102. When piston 62 is in a downstroke position, check valve 114 opens and fluid 54 travels throughfluid passage 112 inside piston 62 where it crosses first check valve114 and exits piston 62, thereby being trapped between first check valve114 and second check valve 120. When piston 62 moves to an up strokeposition, first check valve 114 closes so that fluid 54 may not passback into fluid passage 112. Fluid 54 then travels through pistonhousing outlet 106, into pump outlet passage 118 of pump outlet assembly78 where fluid 54 opens and passes across second check valve 120 andthird check valve 122. When piston 62 moves back to a down strokeposition, second check valve 120 and third check valve 122 close,thereby preventing fluid 54 that has traveled outside of pump 24 fromreentering pump 24 through pump outlet passage 112.

Adjustment screw 74 extends through first surface 82 and second surface84 of main body 56, through opening 34 of top plate 32 of fluidreservoir 20, and into fluid reservoir 20. Adjustment screw 74 is inclose proximity to support post 58 opposite piston housing 60. Pivotjoint 66 connects rocker arm assembly 64 to support post second end 88.Rocker arm assembly 64 extends from pivot joint 66 and support postsecond end 88 towards piston housing 60 and extends between pistonhousing second end 92 and cam 52 of camshaft 18. Rocker arm assembly 64also extends from pivot joint 66 and support post second end 88 towardsadjustment screw 74. Pivot joint 66 permits rocker arm assembly 64 torotate on support post second end 88. Ball and socket joint 68, which isdiscussed in greater detail below with reference to FIGS. 9 and 10,connects piston second end 110 to rocker arm assembly 64 between pistonhousing second end 92 and cam 52. Spring 80 is disposed around pistonhousing 60 and extends between second surface 84 of main body 56 androcker arm assembly 64. When cam shaft 18 is rotated, cam 52 and spring80 move piston 62 between a suction position and a discharge position.Adjustment screw 74 regulates the distance in which spring 80 may pullpiston 62 down towards cam 52 by limiting the distance rocker armassembly 64 may rotate on support post second end 88. Regulating thedistance in which spring 80 may pull piston 62 down towards cam 52regulates the maximum displacement of piston 62 inside piston housing 60and amount of fluid 54 piston 62 pulls into pump 24 per unit measure oftime.

Fluid 54 inside fluid reservoir 20 is typically maintained at a levelsufficient to submerge pump inlet strainer 72, most of pump inlet tube70, camshaft 18, cam 52, and rocker arm assembly 64. As described above,the embodiment of pump 24 in FIG. 4 pumps fluid 54 out fluid reservoir20. As pump 24 pumps fluid 54 out of fluid reservoir 20, pump 24 selflubricates piston 62 with fluid 54. Because pump 24 as embodied in FIG.4 pumps fluid 54 out of fluid reservoir 20, pump 24 is a suction fedpump. Pump 24 may also be configured to be a gravity fed pump or apressure fed pump. In a gravity fed configuration or a pressure fedconfiguration, pump 24 would pump a fluid other than fluid 54 in fluidreservoir 20. This different fluid would be gravity delivered orpressure delivered to pump 24 from some other reservoir and not fluidreservoir 20. This different fluid would be fed directly into fluidpathway 100 at support post first end 86. Because this different fluidwould be fed directly into fluid pathway 100 at support post first end86, pump 24 in a gravity fed configuration or a pressure fedconfiguration will not include pump inlet strainer 72, pump inlet tube70, and pump inlet passage 98, and may not include drip tube 94. Sealassembly 96 fluidly seals piston housing 60 and piston 62 such that thisdifferent fluid from some other reservoir travels through pump 24without leaking into fluid reservoir 20 through piston 62 and pistonhousing 60 and mixing with fluid 54. Thus, camshaft 18, cam 52, androcker arm assembly 64 of pump 24 are able to lubricate in fluid 54inside fluid reservoir 20 while pump 24, in a gravity fed or pressurefed configuration, pumps a fluid different from fluid 54 without the twofluids mixing and contaminating one another.

FIG. 5 is an enlarged cross sectional view of pump 24 of FIG. 4 atsupport post first end 86 and piston housing first end 90. Pump 24 pumpsfluid 54 and includes main body 56, support post 58, piston housing 60,piston 62, sight well 76, pump outlet assembly 78, and drip tube 94. Inthe embodiment of FIG. 5, main body 56 includes first surface 82 andsecond surface 84 (shown in FIG. 4). In the embodiment of FIG. 5,support post 58 includes support post first end 86, support post secondend 88 (shown in FIG. 4), pump inlet passage 98, and fluid pathway 100.In the embodiment of FIG. 5, piston housing 60 includes piston housingfirst end 90, piston housing second end 92 (shown in FIG. 4), bore 102,piston housing inlet 104, and piston housing outlet 106. In theembodiment of FIG. 5, piston 62 includes piston first end 108, pistonsecond end 110 (shown in FIG. 4), fluid passage 112, fluid passage inlet113, first check valve 114, reduced diameter portion 124, and firstrecess 126. In the embodiment of FIG. 5, sight well 76 includes window116. In the embodiment of FIG. 5, pump outlet assembly 78 includes pumpoutlet passage 118, second check valve 120, and third check valve 122.

Components of like numbering as the components disclosed in FIG. 4 areassembled as discussed above with reference to FIG. 4. In the embodimentof FIG. 5, piston 62 is in a down stroke position. First recess 126 isformed in piston first end 108 and has a diameter larger than a diameterof fluid passage 112 yet smaller than a diameter of piston 62. Firstrecess 126 fluidly communicates with fluid passage 112 and pistonhousing outlet 106. First check valve 114 is disposed inside firstrecess 126 and permits fluid 54 to flow out of piston first end 108 intopiston housing outlet 106 while preventing fluid 54 from reenteringfluid passage 112 through piston first end 108. Reduced diameter portion124 is formed on piston 62 between piston first end 108 and pistonsecond end 110, and intersects fluid passage 112 at fluid passage inlet113. As piston 62 moves from a down stroke position to an upstrokeposition and back again, reduced diameter portion 124 ensures that fluidpassage 112 remains fluidly connected at all times to piston housinginlet 104 by providing a constant fluid path between piston housinginlet 104 and fluid passage inlet 113 inside piston 62. When piston 62strokes downward, piston 62 creates a vacuum inside piston housingoutlet 106. The vacuum created by piston 62 in the down stroke positionopens first check valve 114 inside piston first end 108 and pulls fluid54 into pump inlet passage 98 inside support post 58, then across driptube 94, then across fluid pathway 100 inside support post 58 and mainbody 56. The vacuum the pulls fluid 54 across piston housing inlet 104,then between bore 102 and reduced diameter portion 124 of piston 62,then into fluid passage inlet 113 and across fluid passage 112, thenacross first check valve 114 where fluid 54 exits piston 62 andaccumulates inside piston housing outlet 106. Once fluid 54 has finishedaccumulating inside piston housing outlet 106, first check valve 114closes and piston 62 begins to stroke upward. As piston 62 strokesupward, piston first end 108 pushes accumulated fluid 54 out of pistonhousing outlet 106, into pump outlet passage 118 of pump outlet assembly78. The force of fluid 54 entering pump outlet passage 118 opens secondcheck valve 120 and third check valve 122 such that fluid 54 travelsacross second check valve 120 and third check valve 122 where it exitspump 24. As piston 62 strokes downward again, the vacuum created bydownward stroking piston 62 closes second check valve 120 and thirdcheck valve 122 such that fluid 54 that has exited pump 24 will not bepulled back into pump 24.

FIGS. 6A-7 will now be discussed concurrently. FIG. 6A is an enlargedcross sectional view of piston first end 108 from the embodiment of FIG.5, showing first check valve 114 in a closed position. FIG. 6B isanother enlarged cross sectional view of piston first end 108 from theembodiment of FIG. 5 showing first check valve 114 in an open position.FIG. 7 is an exploded perspective view of piston first end 108 from theembodiment of FIGS. 6A and 6B. Piston 62 includes piston first end 108,piston second end 110 (shown in FIG. 4), fluid passage 112, first checkvalve 114, first recess 126, and chamfered surface 128. In theembodiments of FIGS. 6A-7, first check valve 114 includes check ball 130and retaining guide 132. Retaining guide 132 includes outer cylindricalsurface 134, inner cylindrical surface 136, retaining guide first end138 and retaining guide second end 140. In the embodiments of FIGS.6A-7, first recess 126 includes channels 142 and ribs 144. Piston 62pumps fluid 54.

First recess 126 is formed in piston first end 108 and has a diameterlarger than a diameter of fluid passage 112 yet smaller than a diameterof piston 62. First recess 126 is next to fluid passage 112 and isfluidly connected to fluid passage 112. Ribs 144 are formed inside firstrecess 126 and extend substantially the entire depth of first recess 126into piston first end 108. Channels 142 are disposed between ribs 144,which circumferentially space apart channels 142 inside first recess126. Each channel 142 is disposed between two ribs 144. In theembodiment of FIGS. 6A and 6B, three channels 142 and two ribs 144 arevisible. Check ball 130 is disposed inside first recess 126 and has adiameter larger than a diameter of fluid passage 112 yet small enough toallow check ball 130 to move up and down inside first recess 126 alongribs 144 without check ball 130 binding against ribs 144. Chamferedsurface 128 may be disposed between fluid passage 112 and first recess126 and may provide a seat for check ball 130 and aid check ball 130 inclosing off fluid passage 112 when first check valve 114 is in a closedposition.

Retaining guide 132 is shaped as an annular cylindrical pipe, with outercylindrical surface 134 on the outside, inner cylindrical surface 136 onthe inside, and two opposing ends defined by retaining guide first end138 and retaining guide second end 140. When retaining guide 132 isinserted into first recess 126, outer cylindrical surface 134 ofretaining guide 132 abuts against ribs 144 in a press fit, withretaining guide first end 138 disposed at piston first end 108 andretaining guide second end 140 extending into first recess 126 towardscheck ball 130. Inner cylindrical surface 136 of retaining guide 132 issmaller in diameter than check ball 130 such that check ball 130 may notpass through retaining guide 132. First recess 126 accommodates bothcheck ball 130 and retaining guide 132 because the depth first recess126 extends into piston 62 is equal to or deeper than the length ofretaining guide 132 combined with the diameter of check ball 130. Onceinstalled, retaining guide 132 leaves enough space within first recess126 that check ball 130 may move inside first recess 126 between openand closed positions. As discussed above in the description of FIG. 5,first check valve 114 closes as piston 62 strokes upward and first checkvalve 114 opens as piston 62 strokes downward. In the closed position,check ball 130 rests against chamfered surface 128 and blocks fluidpassage 112 such that fluid 54 that has already crossed first checkvalve 114 may not reenter fluid passage 112. In the open position, checkball 130 is raised above chamfered surface 128 and fluid passage 112such that fluid 54 enters first recess 126, flows into channels 142,flows past retaining guide 132 through channels 142, and exits pistonfirst end 108. While the retaining guide 132 is described as an annularcylindrical pipe press-fitted inside first recess 126, it will beunderstood by those skilled in the art that retaining guide 132 may bethreaded or snap fitted into first recess 126, or that retaining guide132 may include a geometry that is different from an annular cylindricalpipe yet still capable of allowing fluid 54 to exit first recess 126while retaining check ball 130 within first recess 126. Becauseretaining guide 132 is generally formed as a single component, retainingguide 132 provides an effective, inexpensive, and simple solution forretaining check ball 130 inside recess 126.

FIG. 8 is an enlarged cross sectional view of piston seal assembly 96from the embodiment of pump 24 described in FIG. 4. Pump 24 includesmain body 56, support post 58, piston housing 60, piston 62, rocker armassembly 64, pivot joint 66, ball and socket joint 68, pump inlet tube70, spring 80, and seal assembly 96. In the embodiment of FIG. 8,support post 58 includes support post first end 86 (shown in FIG. 4),support post second end 88, and pump inlet passage 98. In the embodimentof FIG. 8, piston housing 60 includes piston housing first end 90 (shownin FIG. 4), piston housing second end 92, piston housing inlet 104(shown in FIG. 4), and bore 102. Piston housing 60 further includessecond recess 146. In the embodiment of FIG. 8, piston 62 includespiston first end 108 (shown in FIG. 4), and piston second end 110. Inthe embodiment of FIG. 8, seal assembly 96 includes first elastomericseal 148, second elastomeric seal 150, spacer 152A, spacer 152B, spacer152C and snap ring 154. First elastomeric seal 148 and secondelastomeric seal may be U-cup seals that include fringes 156. Pump 24 islubricated by fluid 54 and may pump fluid 54.

In FIG. 8, components of like numbering with the components of FIG. 4are assembled as discussed above with reference to FIG. 4. Second recess146 is formed in piston housing 60 at piston housing second end 92 andextends from piston housing second end 92 towards piston housing inlet104 without reaching piston housing inlet 104. Second recess 146 has adiameter larger than a diameter of bore 102 so as to accommodate sealassembly 96 and second recess 146 is approximately concentric with bore102 and piston 62. First elastomeric seal 148 and second elastomericseal 150 are each disposed around piston 62 inside second recess 146. Inthe embodiment of FIG. 8, both first elastomeric seal 148 and secondelastomeric seal 150 are U-cup seals. First elastomeric seal 148 isoriented inside second recess 146 and around piston 62 such that itsU-cup geometry and fringes 156 face towards piston housing first end 90.Second elastomeric seal 150 is oriented inside second recess 146 andaround piston 62 such that its U-cup geometry and fringes 156 facetowards piston housing second end 92. As piston 62 actuates inside pump24 and pumps fluid 54, pressure builds-up inside pump 24 and pushesfringes 156 of first elastomeric seal 148 and second elastomeric seal150 against piston 62 and the walls of second recess 146 therebycreating a tight seal that prevents fluid 54 from leaking out of pump 24along piston 62 and second recess 146 at piston housing second end 92.Spacer 152A and spacer 152B are disposed inside second recess 146between first elastomeric seal 148 and second elastomeric seal 150.Along with spacing first elastomeric seal 148 from second elastomericseal 150, spacer 152A and spacer 152B provide backing and support tofirst elastomeric seal 148 and second elastomeric seal 150 to ensurefirst elastomeric seal 148 and second elastomeric seal 150 engage piston62 and second recess 146 evenly. Snap ring 154 is disposed inside secondrecess 146 between piston housing second end 92 and first elastomericseal 148 and second elastomeric seal 150. Spacer 152C is disposedbetween snap ring 154 and first elastomeric seal 148 and secondelastomeric seal 150. Spacer 152C prevents pinching of first elastomericseal 148 by snap ring 154 and ensures that first elastomeric seal 148engages piston 62 and second recess 146 evenly. Snap ring 154 retainsfirst elastomeric seal 148, second elastomeric seal 150, space 152A,spacer 152B, and spacer 152C inside second recess 146. Because of snapring 154 and spacers 152A, 152B, and 152C, seal assembly 96 is easilyinstalled inside second 146 and is easy to replace.

As discussed above in the description of FIG. 4, seal assembly 96fluidly seals piston housing 60 and piston 62 such that pump 24 can pumpfluid 54 without fluid 54 leaking out of pump 24 between piston housing60 and piston 62. Seal assembly 96 is especially useful when pump 24 isconfigured as a gravity fed pump or a pressure fed pump. When pump 24 isa gravity fed pump or a pressure fed pump, pump 24 pumps a fluid otherthan fluid 54. This different fluid is pressure fed or gravity feddirectly into fluid pathway 100 of pump 24 from a reservoir differentfrom fluid reservoir 20 which houses fluid 54 and to which pump 24 ismounted. After this different fluid is fed into fluid pathway 100 ofpump 24, pump 24 pumps it away from pump 24. While pump 24 is pumpingthis different fluid, fluid 54 lubricates rocker arm assembly 64, pivotjoint 66, and ball and socket joint 68. As pump 24 pumps this differentfluid and fluid 54 lubricates rocker arm assembly 64, pivot joint 66,and ball and socket joint 68, seal assembly 96 ensures that thedifferent fluid inside pump 24 does not leak into and contaminate fluid54. Preventing the contamination of fluid 54 by the different fluid inpump 24 ensures the quality of fluid 54 which is selected to optimizethe performance of pump 24. Meanwhile, pump 24 is able to deliver adifferent fluid that meets the requirements of the end to which it isdelivered though pump 24 is lubricated by fluid 54 which is selected tooptimize the performance of pump 24.

FIGS. 9 and 10 will now be discussed concurrently. FIG. 9 is an enlargedcross sectional view of ball and socket joint 68 connecting rockerassembly 64 to piston second end 110 of piston 62 of pump 24 shown inFIG. 4. FIG. 10 is a partial exploded view of the embodiment of FIG. 9.Pump 24 includes main body 56 with second surface 84, support post 58,piston housing 60, piston 62, rocker arm assembly 64, pivot joint 66,ball and socket joint 68, adjustment screw 74, and spring 80. In theembodiment of FIG. 9, support post 58 includes support post second end88, and pump inlet passage 98. In the embodiment of FIG. 9, pistonhousing 60 includes piston housing second end 92, bore 102 (shown inFIG. 4), and second recess 146. In the embodiment of FIG. 9, piston 62includes piston second end 110, rounded surface 158, and annular groove160. In the embodiment of FIG. 9, rocker arm assembly 64 includes arm162, roller 164, roller joint 166, seat 168, and coupler 170. Arm 162includes arm first end 172 and arm second end 174. Seat 168 includesside plates 176 and top plate 178; top plate 178 including dimple 180.Coupler 170 includes prongs 182, sides 184, platform 186, slot 188, andspring guards 190.

In FIGS. 9 and 10, components of like numbering with the components ofFIGS. 4 and 8 are assembled as discussed above with reference to FIGS. 4and 8. Rounded surface 158 of piston 62 is formed on piston second end110, and annular groove 160 is formed on piston 62 between piston firstend 108 and piston second end 110 on a portion of piston 62 that extendsoutside of piston housing second end 92 after piston 62 is installedinside piston housing 60. Pivot joint 66 connects arm 162 of rocker armassembly 64 to support post second end 88 and allows arm 162 to rotate.Arm first end 172 extends from pivot joint 66 towards piston 62 whilearm second end 174 extends from pivot joint 66 towards adjustment screw74. Roller joint 166 connects roller 164 to arm first end 172 and allowsroller 164 to spin on arm first end 172. Seat 168 has two side plates176 that extend from top plate 178 of seat 168 to form a U-shaped yokethat connects to roller joint 166 such that roller 164 is disposedbetween the two side plates 176 and beneath the top plate of seat 168.Because seat 168 is connected to roller joint 166, seat 168 is alsoconnected to arm first end 172. In the embodiment of FIG. 9, only one ofthe two side plates 176 is shown because FIG. 9 is a cross sectionalview. Dimple 180 is centered on top plate 178 of seat 168 and mates withrounded surface 158 of piston 62. Together, rounded surface 158 ofpiston 62 and dimple 180 of seat 168 form ball and socket joint 68.

Coupler 170 connects top plate 178 of seat 168 to piston 62 andmaintains the joint between rounded surface 158 of piston 62 and dimple180 of seat 168. Slot 188 is formed in platform 187 of coupler 170 andmates with annular groove 160 of piston 62 such that platform 187extends into annular groove 160 of piston 62, connecting coupler 170 topiston 62. Coupler 170 is a C-clip with sides 184 extending down fromplatform 186 away from piston 62 and past top plate 178 of seat 168.Prongs 182 extend perpendicularly from sides 184 between top plate 178and arm first end 172, thereby connecting coupler 170 to seat 168.Spring 80 is disposed around piston housing 60 and extends betweensecond surface 84 of main body 56 and platform 186 of coupler 170.Spring guards 190 extend from platform 186 toward piston housing firstend 90 and prevent spring 80 from slipping off of platform 186.

As described above, pump 24 is actuated by camshaft 18 with a cam 52 asshown in FIG. 4. Cam 52 of camshaft 18 rotates against roller 164,causing roller 164 to essentially travel over an arc. As cam 52 rotatesagainst roller 164, cam 52 periodically pushes roller 164, arm first end172, seat 168, piston 62, and coupler 170 towards piston housing firstend 90, compressing spring 80 in the process. Between the periods wherecam 52 is pushing roller 164, arm first end 172, seat 168, piston 62,and coupler 170 towards piston housing first end 90, spring 80decompresses and pushes coupler 170, piston 62, seat 168, arm first end172, and roller 164 away from piston housing first end 90 and towardscam 52. As cam 52 and spring 80 move roller 164, arm first end 172, seat168, piston 62, and coupler 170 back and forth, ball and socket joint 68and coupler 170 ensure that piston 62 remains aligned with bore 102 ofpiston housing 60 by preventing piston second end 110 from shiftinglaterally on seat 168.

In a prior art pump, the piston has a flat second end which has atendency to slip laterally against the rocker arm assembly actuating it.This slipping action in the prior art pump places a bending moment onthe second end of the piston which increases the wear between the pistonand the piston housing, thereby reducing the tolerances between thepiston and the piston housing, and reducing the life of the pump.Because ball and socket joint 68 and coupler 170 prevents piston secondend 110 from slipping, piston 62 and piston housing 60 are able tomaintain tolerances as tight as 0.00045 inches to 0.00025 inches. Suchtight tolerances increase the efficiency of pump 24 by reducing fluidleakage between piston 62 and piston housing 60.

FIG. 11 is an enlarged cross sectional view of another embodiment ofball and socket joint 68 connecting rocker assembly 64 to piston secondend 110 of piston 62 of pump 24. In FIG. 11, components of likenumbering with the components of FIGS. 4, 9, and 10 are assembled asdiscussed above with reference to FIGS. 4, 9, and 10. In the embodimentof FIG. 11, coupler 170 further includes clip 192, and washer 194.

As discussed above, coupler 170 connects top plate 178 of seat 168 topiston 62 and maintains the joint between rounded surface 158 of piston62 and dimple 180 of seat 168. Slot 188 is formed in platform 187 ofcoupler 170 and mates with annular groove 160 of piston 62 such thatplatform 187 extends into annular groove 160 of piston 62. Washer 194and clip 192 are disposed around piston 62 inside annular groove 160 andbetween platform 187 and seat 168. Washer 194 and clip 192 assist inconnecting piston 62 to coupler 170 by preventing platform 187 ofcoupler 170 from slipping out of annular groove 160 of piston 62.

In view of the foregoing description, it will be recognized that thepresent disclosure provides numerous advantages and benefits. Forexample, the present disclosure allows box lubricator 10 to pump a fluiddifferent from fluid 54 used to lubricate pump 24 of box lubricator 10.Moreover, the present disclosure maintains tolerances as tight as0.00045 inches to 0.00025 inches between piston 62 and piston housing 60by reducing the lateral movement of piston second end 110. Additionally,the present disclosure provides an effective, inexpensive, and simpleretaining guide 132 for retaining check ball 130 inside recess 126formed in piston first end 108.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiments disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

1. A box lubricator comprising: a pump comprising; a piston housingextending from a first end to a second end, the piston housingcomprising, a bore extending through the piston housing from the firstend of the piston housing to the second end of the piston housing; arecess disposed at the second end of the piston housing concentric withthe bore and comprising a diameter larger than a diameter of the bore; apiston disposed inside the bore of the piston housing and comprising afirst end opposite a second end; and at least one elastomeric sealdisposed inside the recess of the piston housing and around the piston;2. The box lubricator of claim 1, further comprising; a support post inclose proximity to the piston housing and comprising a first endopposite a second end; a piston housing inlet intersecting the borebetween the first end of the piston housing and the recess; and a pistonhousing outlet disposed at the first end of the piston housing and influid communication with the bore; and a main body joining the supportpost and the piston housing, the main body including a fluid pathwayfluidly connecting the piston housing inlet with the first end of thesupport post.
 3. The box lubricator of claim 2, wherein the at least oneelastomeric seal is a U-cup seal.
 4. The box lubricator of claim 3,wherein there are two elastomeric seals disposed inside the recess ofthe piston housing and around the piston.
 5. The box lubricator of claim4, wherein a snap ring is disposed inside the recess of the pistonhousing and retains the two elastomeric seals inside the recess of thepiston housing.
 6. The box lubricator of claim 5, wherein at least twospacers are disposed between the two elastomeric seals and anotherspacer is disposed between the snap ring and the at least twoelastomeric seals.
 7. The box lubricator of claim 1, further comprising;a fluid reservoir comprising; a top plate and an opening formed in thetop plate; and wherein the pump is mounted to the top plate of the fluidreservoir such that the first end of the support post and the first endof the piston housing are disposed outside of the fluid reservoir andthe second end of the support post and the second end of the pistonhousing extends into the fluid reservoir through the opening in the topplate of the fluid reservoir.
 8. The box lubricator of claim 7, furthercomprising; a camshaft extending horizontally into the fluid reservoirand comprising a cam a rocker arm assembly pivotally connected to thesecond end of the support post, the rocker arm assembly extendingbetween the cam of the camshaft and the second end of the piston, andconnected to the second end of the piston by a ball and socket joint; afluid is disposed inside the fluid reservoir and lubricates the pump;and wherein the pump is fluidly connected to a separate reservoircontaining a different fluid from the fluid in the fluid reservoir andthe pump pumps the different fluid.